Usually, photolithographic technique has been used as a method of forming/processing a device having a microstructure such as a semiconductor device or a circuit board used in a wide range of technical fields. Accompanied by the sophistication of required performance, in these fields, the miniaturization, high-density integration and speed-up of a semiconductor device and the like are significantly advanced, and a resist pattern used for photolithography is miniaturized, and aspect ratio of the resist pattern keeps increasing. Accompanied by the advance of such miniaturization, however, collapse of the resist pattern becomes a major problem.
It has been known that collapse of a resist pattern is caused by action of stress due to surface tension of a treatment liquid, upon drying the resist pattern to remove the treatment liquid used in wet treatment (which intends to mainly a rinsing treatment for washing away a developing solution) following a development of the resist pattern. For the resolution of collapse of a resist pattern, such methods have been proposed as a method of replacing a rinsing liquid by a liquid with low surface tension comprising a nonionic surfactant, a compound soluble in an alcohol solvent or the like and then drying (see, for example, Patent Literatures 1 and 2), and a method of having a surface of resist pattern hydrophobic (see, for example, Patent Literature 3).
Here, in a microstructure comprising metal, metal nitride, metal oxide, silicon oxide, silicon or the like which is formed by photolithography technique (except a resist; the same hereinafter, unless otherwise indicated), the strength of material in itself of which the structure is formed is larger than the strength of a resist pattern in itself or the bonding strength between a resist pattern and a substrate. Therefore, the structure pattern is hard to collapse as compared to the resist pattern. However, accompanied by the advance of miniaturization, high-density integration or speed-up of a semiconductor device, a micromachine or the like, the collapse of structure pattern due to the miniaturization of structure pattern and an increase of aspect ratio becomes a major problem.
There, for the resolution of collapse of a microstructure pattern, a method of forming a water repellent protective film using a surfactant has been proposed (see, for example, Patent Literature 4). However there is no specific description about kind (for example, nonionic, anionic or cationic), a product name, the content or the like of the surfactant at all.
Further, a method of forming a water repellent protective film onto a rough pattern surface on a surface of wafer comprising metal material in part by using a variety of non-water soluble surfactants has been proposed (see, for example, Patent Literature 5). However, for using a treatment liquid for inhibiting pattern collapse comprising the non-water soluble surfactant, an organic solvent, a mixture of the said organic solvent and an aqueous rinsing liquid, and a rinsing liquid mixing those with at least one of acid and alkali are required as pre-treatment liquids. Thus, the number of processes for forming the protective film is a lot and complicated, so it is desired to lessen the number of such processes.
Furthermore, a method of forming a water repellent protective film onto a rough pattern surface on a surface of wafer comprising metal material by using a treatment liquid for inhibiting pattern collapse comprising an alkylamine and water has been proposed (see, for example, Patent Literature 6). However, as for a pattern with high aspect ratio, pattern collapse cannot be inhibited (see Comparative Examples 8, 17 and 26 as described hereinbelow).                [Patent Literature 1] JP 2004-184648A        [Patent Literature 2] JP 2005-309260A        [Patent Literature 3] JP 2006-163314A        [Patent Literature 4] JP 2010-114467A        [Patent Literature 5] JP 2012-9802A        [Patent Literature 6] JP 2012-33890A        